Search warrant information released by the state earlier this year did not indicate whether drugs or alcohol were found in the home Lanza shared with his mother. But they did show that unspecified medical records were found, the Courant reported.

The massacre brought to light mental health issues.

Experts said previous mass shooting suspects also tested clean for drugs, indicating that the massacres were deliberate and thought-out actions.

Lanza killed his mother as she slept in her bed on the morning of Dec. 14 before driving to Sandy Hook Elementary School and carrying out one of the worst massacres in U.S. history.

In the months since the shooting rampage, New York and Connecticut have instituted stricter gun laws. Some families of the victims have lobbied members of Congress to strengthen the nation’s gun laws by implementing universal background checks and other measures.

A bipartisan bill on background checks was blocked by a Republican-led filibuster.